Cavichioli, D. Carnovale, C.
Scale formation is one of the most critical challenges to control the mud settling performance in a lead Washer and to extend the vessel life. The first impacts refinery throughput and operational costs, with high flocculent usage and poor caustic recovery. The second is directly related to maintenance costs. Rio Tinto Yarwun alumina refinery has been working to improve the performance of its lead Washers through a series of improvement projects with successful results. In order to address the scale formation issue, the Nalco ScaleGuard program was trialled in the plant with promising results. This paper describes the method applied for the plant trial and its results.